The cause of death of a pygmy sperm whale that washed ashore in Myrtle Beach is not clear following Monday’s necropsy.

Wayne McFee, with the National Oceanic and Atmospheric Association, said Monday the heart condition of the whale suggested cardiomyopathy — a weakening of the heart muscles — but he said the cause won’t be known until results of further testing return. Testing could take weeks, he said.

The whale was found beached near 18th Avenue North before 6 p.m. Sunday, and was euthanized about 8:45 p.m.

McFee said the whale measured 323 centimeters (about 10.5 feet) and weighed close to 1,000 pounds. Its age will not be determined until the teeth are sectioned and examined, he said.

Though pygmy sperm whales are common to the Atlantic waters, McFee said they’re not often seen.

“We don’t see them at sea very much because they’re very shy,” he said. “They don’t approach boats. When they surface near boats they tend to take a breath then disappear. We know they’re deep water animals.”

McFee said pygmy sperm whales are the second most commonly stranded cetacean (dolphins and whales) on the east coast.

When large animals such as a whale are found live on the shore, McFee said they shouldn’t be pushed back into the water for a few reasons.

“One, these are very large animals,” he said. “They’re very powerful and they can cause severe injury to people trying to do that if they want to.”

Also, he said if the animal is washed ashore, it’s likely for a reason.

“They’re probably dying,” McFee said. “If you push them back out, you expose them” to predators.

In the case of the whale found in Myrtle Beach on Sunday, he said “it was certainly sick” and had a “heavy load of parasites.”

“They wouldn’t be this close to shore if they weren’t sick,” he said. “These animals are deep water animals and shouldn’t be here unless something’s wrong.”